The present invention relates to magnetic recording heads, and more particularly, this invention relates to ion milling for magnetic recording heads.
In magnetic storage systems, data is read from and written onto magnetic recording media utilizing magnetic transducers commonly. Data is written onto the magnetic recording media by moving a magnetic recording transducer to a position over the media where the data is to be stored. The magnetic recording transducer then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read transducer and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media.
An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has lead to increasing the track density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head assembly for use in such systems.
In a tape drive system, magnetic tape is moved over the surface of the tape head at high speed. This movement generally entrains a film of air between the head and tape. Usually the tape head is designed for minimizing the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial so that the recording gaps of the write transducers, which are the source of the magnetic recording flux, ideally contact the tape to effect efficient signal transfer, and so that the read elements ideally contact the tape to provide effective coupling of the magnetic field from the tape to the read element.
One particular problem which may be encountered when tape is moved over the surface of the tape recording head is the tape induced bridging of metallic portions of the thin films across the top portions of the films. As a result, thin films which are to be insulated from each other may actually come into electrical contact with each other, which in time may result in shorting and failure of the head. This effect can be seen in FIG. 2D, and will be explained in more detail later. Therefore, it would be favorable to have a technique of selectively altering the surface heights of thin films, allowing an insulator to have a higher surface height than surrounding poles or shields, to minimize this bridging effect.
Additionally, the thin entire film region may be recessed from the surrounding components, such as the substrate and closure, so that the tape will rarely come into contact with the head components in the thin film region. One method to recess the thin film region is plasma etching, such as argon plasma etching. However, as is well known, an argon plasma etches nickel iron alloys and some other metals commonly used in magnetic heads much more rapidly than the surrounding insulators. Thus, while plasma etching may produce an overall recession for all materials in the gap, the amount of etching required to produce the desired overall recession may produce excessive magnetic pole, sensor, and shield recession, and thus lead to excessive spacing loss.
What is needed is a method to produce overall recession without excessive metal recession.